1. Field of the Invention
The present invention relates to a method of utilizing an air conditioner including a plurality of environmental factor adjusting devices to control thermal comfort level of an environment, and more particularly, to a method of controlling an environment thermal comfort level which can attain an optimal energy saving goal.
2. Description of the Prior Art
International standards ISO 7730 and ASHRAE 55 both use predicted mean vote (PMV) index and predicted percent dissatisfied (PPD) to describe and estimate thermal comfort level of an environment. The PMV index represents feelings about the temperatures of most people in the same environment, and the PPD index represents a percentage of people unsatisfied with the environment. In addition, please note that the PMV-PPD index comprehensively considers six factors of human activity level, clothing thermal resistance, air temperature, average radiation temperature, air velocity and air humidity. Please refer to FIG. 1. FIG. 1 is a diagram of a relation between the PMV index and the PPD index.
In current buildings, most thermal comfort level control system mainly adjusts the temperature or humidity individually without considering comprehensive estimation of the thermal comfort level, as well as other factors that can affect the thermal comfort level. Thus, when the temperature is adjusted to an ideal level, it is possible that people still feel uncomfortable since the effects of the air velocity and air humidity are not considered.
In addition, since the conventional thermal comfort level control system only considers a single factor (such as the temperature or humidity), improvements to the air conditioner can only focus on Energy Efficiency Ratio (EER), and improvements to the dehumidifier can only focus on Efficiency Factor (EF). Thus, using the conventional thermal comfort level control system will consume more energy in general.